WO1997038497A1 - Procede de codage d'un signal audio numerise avec une basse frequence d'echantillonnage - Google Patents

Procede de codage d'un signal audio numerise avec une basse frequence d'echantillonnage Download PDF

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Publication number
WO1997038497A1
WO1997038497A1 PCT/EP1997/000792 EP9700792W WO9738497A1 WO 1997038497 A1 WO1997038497 A1 WO 1997038497A1 EP 9700792 W EP9700792 W EP 9700792W WO 9738497 A1 WO9738497 A1 WO 9738497A1
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WO
WIPO (PCT)
Prior art keywords
scale factor
standard
region
audio signal
frequency lines
Prior art date
Application number
PCT/EP1997/000792
Other languages
German (de)
English (en)
Inventor
Oliver Kunz
Martin Dietz
Rainer Buchta
Jürgen Zeller
Karlheinz Brandenburg
Martin Sieler
Heinz GERHÄUSER
Original Assignee
Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=7790553&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=WO1997038497(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Priority to DE59700044T priority Critical patent/DE59700044D1/de
Priority to RU98110809A priority patent/RU2134016C1/ru
Priority to CA002241453A priority patent/CA2241453C/fr
Priority to EP97906097.7A priority patent/EP0832521B3/fr
Priority to DK97906097T priority patent/DK0832521T3/da
Priority to AU20916/97A priority patent/AU703390B2/en
Priority to US09/077,395 priority patent/US6185539B1/en
Application filed by Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. filed Critical Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority to US13/897,221 priority patent/USRE44897E1/en
Priority to UA98052380A priority patent/UA48195C2/uk
Priority to JP09535776A priority patent/JP3103382B2/ja
Priority to KR1019980703652A priority patent/KR100266054B1/ko
Priority to ES97906097.7T priority patent/ES2125739T7/es
Publication of WO1997038497A1 publication Critical patent/WO1997038497A1/fr
Priority to NO19982920A priority patent/NO315298B1/no

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/66—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/66—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission
    • H04B1/665—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for reducing bandwidth of signals; for improving efficiency of transmission using psychoacoustic properties of the ear, e.g. masking effect

Definitions

  • the present invention relates to a method for coding an audio signal digitized with a low sampling rate.
  • the invention is concerned with a coding method which is only slightly modified compared to the IS0-MPEG2 Layer 3 standard and which enables audio signals which are digitized with a lower sampling rate than the sampling rate according to the ISO-MPEG2 Layer 3 standard at a low bit rate.
  • the existing standard ISO 13818-3 defines with layer 3 a coding method for signals with sampling frequencies between 24 kHz and 16 kHz and enables bit rates down to 8 kbit / s. In particular at this very low bit rate, which is very attractive for transmission in computer networks, for example, the use of even lower sampling frequencies would be desirable. However, the standard mentioned does not make this available.
  • the present invention is therefore based on the object of developing the above-mentioned method for coding audio signals in such a way that sampling with non-standard-conforming sampling rates is carried out with the smallest possible deviation from the standard can, whereby decoding with existing decoders should be possible without major adaptation effort.
  • This object is achieved by a method according to claim 1.
  • the invention provides for encoding audio signals which are digitized at a sampling rate which is lower than the sampling rate according to the ISO-MPEG2 Layer 3 standard.
  • the adjacent frequency lines of the digitized audio signal which are assigned to a scale factor band are coded with the same scale factor which is transmitted together with the coded scale factor band.
  • adjacent scale factor bands form a region within which all scale factors are coded with the same number of bits, which is determined according to the largest scale factor of this region.
  • scale factors are assigned to all scale bands in all regions. Only the last band, in which the remaining frequency lines are when the frequency lines are divided, does not have a scale factor when coding according to the standard mentioned.
  • the invention provides that at least the frequency lines of the uppermost region of scale factor bands are coded with the scale factor 0, so that no scale factor is coded and transmitted for the at least uppermost region.
  • the bits saved by the omitted scale factor or the omitted scale factors are used for the quantization of the frequency lines in the rest of the spectrum, which is finer than the standard.
  • the division of the frequency lines into scale factor bands has been modified compared to the standard mentioned in such a way that the scale factor bandwidths within the uppermost region are reduced compared to the scale factor bandwidths of the uppermost region according to the IS0-MPEG2 Layer 3 standard.
  • a frame header modified compared to the standard MPEG frame header is used in order to signal the non-standard-conforming sampling rate and the non-standard conform coding for a decoder.
  • the sync word "FFE” (eleven ones and one zero) is introduced inside the header instead of the hexadecimal sync word "FFF" (hexadecimal for twelve ones). If a decoder recognizes a sync word modified in this way, this is an indication that the bit stream contains a signal which, compared to the MPEG2 standard, was digitized with the preferably half sampling rate (12 kHz, 11.025 kHz or 8 kHz). Otherwise the structure of the bit stream remains unchanged compared to the standard.
  • the division of the frequency lines into scale factor bands is also modified.
  • a construction in the bitstream format of layer 3 is used, with the aid of which the number of bits available for coding the spectrum can be increased.
  • the table of the scale factor bandwidths is changed for the sampling rate 8 kHz in such a way that the uppermost region in the spectrum contains very few lines which are generally not used or are used only little due to bandwidth restrictions.
  • the scale factors of the scale factor bands of the uppermost region are set to zero without exception, so that no coding of the scale factors is necessary.
  • the spectrum is effectively divided into 17 scale factor bands without, however, having to leave the bitstream syntax of the MPEG2 standard.
  • the tables for the scale factor bandwidths are shown below.
  • the first-mentioned table for the widths of the scale factor bands for a 16 kHz sampling rate corresponds to the standard ISO MPEG Layer 3.
  • the second-mentioned table is modified according to the teaching of the invention for the 8 kHz sampling rate.
  • Widths of the scale factor bands for 16 kHz sampling rate (for comparison according to standard)
  • the last scale factor bandwidths in the method according to the invention have been significantly reduced compared to the known standard method.
  • the last 100 frequency lines are coded without a scale factor. This corresponds to a restriction of the possible bandwidth from 4000 Hz to 3300 Hz.
  • the desired effect can therefore be achieved if the bandwidth used is less than 3300 Hz, which is a bit rate of 8 kbit / s for which the 8 kHz sampling rate is thought, certainly makes sense.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
  • Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)

Abstract

Selon un procédé de codage d'un signal audio numérisé avec une basse fréquence d'échantillonnage, plusieurs lignes de fréquences contiguës du signal audio numérisé, qui sont attribuées à une bande de facteurs de proportionnalité, sont chaque fois codées avec le même facteur de proportionnalité. Ainsi des bandes de facteurs de proportionnalité contiguës forment une région, à l'intérieur de laquelle tous les facteurs de proportionnalité sont codés chaque fois avec un même nombre de bits, qui est défini d'après le plus grand facteur de proportionnalité de la région. Les lignes de fréquences d'au moins la région la plus élevée des bandes de facteurs de proportionnalité sont codées avec le facteur de proportionnalité 0. Pour ladite région la plus élevée aucun facteur de proportionnalité n'est codé.
PCT/EP1997/000792 1996-04-04 1997-02-19 Procede de codage d'un signal audio numerise avec une basse frequence d'echantillonnage WO1997038497A1 (fr)

Priority Applications (13)

Application Number Priority Date Filing Date Title
ES97906097.7T ES2125739T7 (es) 1996-04-04 1997-02-19 Procedimiento para codificar una señal audio digitalizada con una velocidad de exploración baja
US09/077,395 US6185539B1 (en) 1996-04-04 1997-02-19 Process of low sampling rate digital encoding of audio signals
CA002241453A CA2241453C (fr) 1996-04-04 1997-02-19 Procede de codage d'un signal audio numerise avec une basse frequence d'echantillonnage
EP97906097.7A EP0832521B3 (fr) 1996-04-04 1997-02-19 Procede de codage d'un signal audio numerise avec une basse frequence d'echantillonnage
DK97906097T DK0832521T3 (da) 1996-04-04 1997-02-19 Fremgangsmåde til kodning af et med en lavere sampling-frekvens digitaliseret audiosignal
AU20916/97A AU703390B2 (en) 1996-04-04 1997-02-19 Method for coding an audio signal digitized at a low sampling rate
US13/897,221 USRE44897E1 (en) 1996-04-04 1997-02-19 Process of low sampling rate digital encoding of audio signals
DE59700044T DE59700044D1 (de) 1996-04-04 1997-02-19 Verfahren zum codieren eines mit einer niedrigen abtastrate digitalisierten audiosignals
RU98110809A RU2134016C1 (ru) 1996-04-04 1997-02-19 Способ кодирования оцифрованного с низкой частотой дискретизации аудиосигнала
UA98052380A UA48195C2 (uk) 1996-04-04 1997-02-19 Спосіб кодування аудіосигналу, оцифрованого з низькою частотою дискретизації
JP09535776A JP3103382B2 (ja) 1996-04-04 1997-02-19 低サンプリング・レートでデジタル化されたオーディオ信号を符号化する方法
KR1019980703652A KR100266054B1 (ko) 1996-04-04 1997-02-19 낮은 샘플링 속도에서 디지탈화된 오디오 신호를 코딩하는 방법
NO19982920A NO315298B1 (no) 1996-04-04 1998-06-23 Fremgangsmåte for koding av et lydsignal som er digitalisert med en lav samplingsfrekvens

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19613643A DE19613643A1 (de) 1996-04-04 1996-04-04 Verfahren zum Codieren eines mit einer niedrigen Abtastrate digitalisierten Audiosignals
DE19613643.1 1996-04-04

Publications (1)

Publication Number Publication Date
WO1997038497A1 true WO1997038497A1 (fr) 1997-10-16

Family

ID=7790553

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1997/000792 WO1997038497A1 (fr) 1996-04-04 1997-02-19 Procede de codage d'un signal audio numerise avec une basse frequence d'echantillonnage

Country Status (14)

Country Link
US (2) US6185539B1 (fr)
EP (1) EP0832521B3 (fr)
JP (1) JP3103382B2 (fr)
KR (1) KR100266054B1 (fr)
AT (1) ATE174167T1 (fr)
AU (1) AU703390B2 (fr)
CA (1) CA2241453C (fr)
DE (2) DE19613643A1 (fr)
DK (1) DK0832521T3 (fr)
ES (1) ES2125739T7 (fr)
NO (1) NO315298B1 (fr)
RU (1) RU2134016C1 (fr)
UA (1) UA48195C2 (fr)
WO (1) WO1997038497A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000137497A (ja) * 1998-10-29 2000-05-16 Ricoh Co Ltd デジタル音響信号符号化装置、デジタル音響信号符号化方法及びデジタル音響信号符号化プログラムを記録した媒体

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3515903B2 (ja) * 1998-06-16 2004-04-05 松下電器産業株式会社 オーディオ符号化のための動的ビット割り当て方法及び装置
US8290782B2 (en) * 2008-07-24 2012-10-16 Dts, Inc. Compression of audio scale-factors by two-dimensional transformation
DE102009028919A1 (de) 2009-08-27 2011-03-03 Robert Bosch Gmbh Verfahren und Steuergerät zur Direktabtastung einer Mehrzahl von Radiobändern
JP5316896B2 (ja) * 2010-03-17 2013-10-16 ソニー株式会社 符号化装置および符号化方法、復号装置および復号方法、並びにプログラム
US8552900B1 (en) * 2012-04-20 2013-10-08 Texas Instruments Incorporated System and method of clocking low sample rate analog to digital converters while minimizing linearity errors

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0457391A1 (fr) * 1990-05-14 1991-11-21 Koninklijke Philips Electronics N.V. Méthode de codage et dispositif de codage comportant un codeur de sous-bande et émetteur muni du dispositif de codage
EP0525774A2 (fr) * 1991-07-31 1993-02-03 Matsushita Electric Industrial Co., Ltd. Système et procédé de codage d'un signal audio numérique
EP0612159A2 (fr) * 1993-02-19 1994-08-24 Matsushita Electric Industrial Co., Ltd. Procédé d'amélioration d'un quantificateur grossier dans un codeur du type ATRAC

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4236989C2 (de) * 1992-11-02 1994-11-17 Fraunhofer Ges Forschung Verfahren zur Übertragung und/oder Speicherung digitaler Signale mehrerer Kanäle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0457391A1 (fr) * 1990-05-14 1991-11-21 Koninklijke Philips Electronics N.V. Méthode de codage et dispositif de codage comportant un codeur de sous-bande et émetteur muni du dispositif de codage
EP0525774A2 (fr) * 1991-07-31 1993-02-03 Matsushita Electric Industrial Co., Ltd. Système et procédé de codage d'un signal audio numérique
EP0612159A2 (fr) * 1993-02-19 1994-08-24 Matsushita Electric Industrial Co., Ltd. Procédé d'amélioration d'un quantificateur grossier dans un codeur du type ATRAC

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000137497A (ja) * 1998-10-29 2000-05-16 Ricoh Co Ltd デジタル音響信号符号化装置、デジタル音響信号符号化方法及びデジタル音響信号符号化プログラムを記録した媒体

Also Published As

Publication number Publication date
ES2125739T7 (es) 2014-04-08
DE59700044D1 (de) 1999-01-14
EP0832521B1 (fr) 1998-12-02
ATE174167T1 (de) 1998-12-15
US6185539B1 (en) 2001-02-06
KR19990067625A (ko) 1999-08-25
KR100266054B1 (ko) 2000-09-15
EP0832521B3 (fr) 2014-01-15
JPH11507198A (ja) 1999-06-22
RU2134016C1 (ru) 1999-07-27
EP0832521A1 (fr) 1998-04-01
AU703390B2 (en) 1999-03-25
NO315298B1 (no) 2003-08-11
USRE44897E1 (en) 2014-05-13
DE19613643A1 (de) 1997-10-09
ES2125739T3 (es) 1999-03-01
JP3103382B2 (ja) 2000-10-30
CA2241453A1 (fr) 1997-10-16
NO982920L (no) 1998-07-23
UA48195C2 (uk) 2002-08-15
CA2241453C (fr) 2002-01-29
DK0832521T3 (da) 1999-08-16
NO982920D0 (no) 1998-06-23
AU2091697A (en) 1997-10-29

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